Printing telegraph apparatus and system



Feb. 29, 1944. P. a. MURPHY 2,342,386

PRINTING TELEGRAPH APPARATUS AND SYSTEM Filed Feb. 25, 1941 s Sheets-Sheet 1' FIG.

INVENTOR P. B. MURPHY AT. TORNEK P. B. MURPHY PRINTING TELEGRAPH APPARATUS AND SYSTEM 3 Sheets-Sheet 2 Feb. 29, 1944.

Filed Feb. 25, 1941 lNl EN TOR 9B. MURPH V I ATTORNEY Feb. 29, 1944. P. B. MURPHY PRINTING TELEGRAPH APPARATUS AND SYSTEM Filed Feb. 25, 1941 3 Sheets-Sheet I5 Patented Feb. 29, 1944 um'rso. STATE-S PATENT OFFICE PRINTINGTELEGRAPH APPARATUS AND SYSTEM Pauil B. Murphy, S outh Nyack, N. Y., assignor to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application February 25, 1941, Serial No. 380,433

13 Claims.

This invention relates to telegraph apparatus and systems and particularly to printing telegraph signal transmission and reception.

An object of the invention is to generate oscillatory signaling current at audible frequencies by means of a vibrating reed generator.

Another object of the invention is to set in vibration simultaneously'variably selectable ones of a plurality of vibratory reeds according to signals to be transmitted. v j

A further object of the invention is to receive simultaneously transmitted oscillatory signaling current and to channel those currents to individual signal responsive devices for efiecting the selection and operation of a recording element such as a type bar of a printing recorder.

In general, the invention contemplates a transmitter including code elements and code element operating means such as key levers for operating the code elements in various combinations according to signals to be transmitted. A magnet structure supports a plurality of vibratory reeds, equal in number to the number of code elements, of different effective dimensions so as to have different natural frequencies of vibration. The reeds are set in vibration in combinations simultaneously by'their individual code elements, and the vibrating reeds generate in a pick-up coil, oscillatory currents at frequencies corresponding to the frequencies of vibration of the reeds. These oscillatory currents are impressed upon a telegraph signaling channel.

At the receiver, the oscillatory currents are amplified, are separated by individual filters tuned to the several frequencies and are rectified by individual rectifiers. Each of the rectified currents operates an individual selector relay and two or more of the relays in combinations cooperate to effect the energization selectively of electromagnets individually connected to the key levers of a printing recorder which has its type bars connected directly to the key levers for operation thereby. The keylevers are the same ones which control the code elements of the transmitting mechanism local to the receiving printer, so that home recording of a message to be transmitted is accomplished mechanically through the manual operation of the key levers. .A sendreceive switch selectively connects the transmitter or the receiver of a combined set to the communication channel, so that when a message is being transmitted the signals do not operate the local selecting and-printing mechanism, such operatiqn'of, thfi selecting and printing mechanism not being necessary in view of the directproduction of the home record through operation of the key levers.

For a complete understanding of the invention reference may be had to the following detailed description to be interpreted in the light of the accompanying drawings wherein:

Fig. 1 is a schematic view of a signal transmitting and receiving system in accordance with the present invention; v

Fig. 2 is a diagrammatic perspective view of a keyboard transmitter and recorder indicated schematically in Fig. 1;

Fig. 3 is an elevational view taken at one end of the vibrating reed generator shown in Fig. v2;

Fig.4 is a vertical sectional view taken on the line 4-4 of Fig. 3; and

Fig. 5 is a'diagrammatic perspective view of a modified form of keyboard transmitter.

Referring now to the drawings and particularly to Fig. 1, the reference numeral H designates a pair of conductors which serve as a communication channel. At the left-hand end of the line I l, which may be designated as the west end, the line conductors are connected to the swinger springs l2 of a send-receive key designated generally by the reference numeral l3. Key i3 is of the double pole, double throw type and its outer stationary springs M are connected by conductors Hi to a transmitter l'l indicated schematically in Fig. 1 and in detail in Fig. 2.

The transmitter I! (Fig. 2) is provided with a bank of key levers l8 pivoted at the rear of the machine on a common pivot rod I9. The key levers l8 are individually provided with finger key tops 2| and in Fig. 2 four rows of such key tops have been shown. This arrangement corresponds to the key top arrangement of common species of commercially available typewriting machines. The communication system according to the present invention is adaptable to operation by a keyboard of the type provided on typewriting machines which includes four rows of key tops, the typing of figures being accomplished without interposing a shift function, and thus such machines may be employed as telegraph transmitters and printers. the keyboard mechanism includes a space bar 22, and keys not involved directly in the selection of a character or symbol but involved instead in the selection, of a function, as exemplified by the shift key 23. I

At the opposite sides of the keyboard mechanism, rods 24 extending parallel to the key levers l8 are stationarily supported and, thev rods 24 IO As shownin Fig. 2

tatably support antifriction rollers 25. The antifriction rollers 26 are disposed in obliquely extending slots 21 near the opposite ends of code bars 23 which extend transversely of the key levers l8 and below them. The code bars 28 are maintained in the desired spaced positions along the rods 24 by one or more comb plates 29 which restrict lateral movement of the code bars but which freely permit vertical movement and end wise movement of those bars. By means of the obliquely extending slots 21 code bars 28 are permitted to undergo endwise movement and vertical movement in their own planes, and the code bars are biased by tension springs 3| to their lefthand and uppermost positions as determined by slots 21.

Key levers l8, including the levers by which space bar 22 is supported, are provided with depending code lugs 32 which are variously presented above the code bars 28 in accordance with the signaling code, it being understood that no two key levers have the same combinational arrangement of lug 32. Upon the depression of any one of the key levers l8 its associated code lugs 32 press downwardly on the upper edges of the code bars 28 that are disposed beneath them and the slots 21 in the code bars cause them to move rightwardly as viewed in Fig. 2 as Well as downwardly. Upon the release of a depressed key lever la the springs 3| associated with those of the code bars 28 which were depressed by the key lever restore their code bars to normal position which is the extreme upper and left-hand position.

Near their left-hand ends as viewed in Fig. 2 the code bars 28 pivotally support short plucking levers 33 that are individually biased in counterclockwise direction by tension springs 34 into engagement with stop pin 36 individually carried by the code bars 28. The upper ends of the plucking levers 33 are disposed to the left of and above the lower ends of vibratory reeds 31 contained in a signal generator indicated generally by the reference numeral 38.

Structural details of the signal generator 38 are shown in Figs. 3 and 4. The signal generator includes a permanent magnet 39 which in cross-section is C-shaped to provide opposed magnetic poles M. The magnet 39 is of sufiicien-t length to span transversely the code bars 28. Supported inside magnet 39 approximately in a central position with respect to the opposed poles M are clamping plates 42 for the vibratory reeds 31 extending longitudinally of magnet 39 and parallel to the poles 4 I. The width of the clamping plates 42 preferably is graduated in steps from end to end so as to leave graduated lengths of the reeds 31. free to vibrate. Thus the reeds 31 may all be identical, but as they are damped at varying distances from their lower ends they will have different natural frequencies of vibration. As six vibratory reeds 31 are shown in the drawings it may be convenient to dimension and damp the reeds so that they shall vibrate at the frequencies 700, 900, 1100, 1300, 1500 and 1700 cycles per second, these being frequencies that certain well-known telephone apparatus is adapted to accommodate. By employing frequencies that are contemplated by known telephone apparatus, telephone circuits may be employed for the transmission and reception of the telegraph signals which the apparatus in accordance with the present invention generates. However, the invention is not limited to these frequencies and any convenient combination of frequencies may be employed. As viewed in Fig. 4 the left-hand reed would vibrate at 700 cycles per second and the right-hand reed would vibrate at 1700 cycles per second, with the intermediate reeds vibrating at the intermediate frequencies mentioned above.

The vibratory reeds 31 are of magnetic material and serve as driving armatures for a pick-up coil Winding 43 which extends around all of the reeds 31. It will be understood that instead of a single pick-up coil to be energized by the vibration of any or all of the reeds 31 a plurality of pick-up coils individual to the reeds could be provided.

In the operation of the transmitter shown in Figs. 2, 3 and 4 the key levers l8 are operated in succession by finger operation of the key tops 21 in accordance with the message to be transmitted. As a key lever is depressed its lugs 32 depress certain of the code bars 28 in accordance with the signal to be transmitted and the slots 21 cause the code bars to move rightwardly as well as downwardly. Since the plucking levers 33 are estopped from rotating counterclockwise by pins 36 the upper ends of the levers 33 move into engagement with the associated ones of the vibratory reeds 31 and flex those reeds in the direction of endwise movement of the code bars. The levers 33 are moved bodily in an oblique direction corresponding to that of the code bars 28 but the overlap between the levers 33 .and the reeds 31 is sufficient that the reeds will be deflected to the right before the upper ends of the levers 33 are moved clear of the lower ends of reeds .31 and permit the reeds to escape. When the reeds 31 have escaped they will vibrate at their natural frequencies and will induce in the pick-up coil 43 oscillatory currents at frequencies corresponding to the frequencies of vibration of the reeds.

As the reeds 31 vibrate their amplitude of vibration decreases and the strength of the signaling currents generated correspondingly decreases. However, the reeds will vibrate at a sufficient amplitude to generate effective signaling currents for a suflicient length of time to effect adapted to accommodate the generation of signals at a rate as fast as that attained by expert keyboard operators, so that the key levers need not be held depressed for excessive lengths of time.

Upon the release of pressure on the key levers the springs 3! connected to those of the code bars 28 which have been depressed restore the code bars to their extreme left-hand and upper positions. The plucking levers 33, in returning to their normal positions, encounter the righthand faces of the reeds 31 and damp out vibration of the reeds. As movement of levers 33 to the right continues, the springs 34 yield and permit levers 33 to be rocked clockwise for the purpose of moving past the lower ends of reeds 31. When the levers 33 have escaped from the lower ends of the reeds, springs 34 restore the levers to extreme counterclockwise position with their lower ends in engagement with stop pins 36.

Referring again to Fig. 1, it is to be understood that the rectangle 5l represents a station at the right-hand or east end of communication channel ll including transmitting and receiving apparatus duplicating that shown connected to the left-hand or west end of communication 2,34aeae channel H. Assuming that the station is to transmit message material westwardly over chan-.

nel H the key l3 at station 5| would be operated to bring its swinger springs l2 into engagement with the outer stationary contacts |4 to connect the transmitter I! at station 5| to channel The normal or idle condition of key I3 at either of the stations connected to channel II is that shown in Fig. 1 with the swinger springs I2 in engagement with the inner stationary contacts 52. These contacts are connected to the ends of the primary windings of an input transformer for an amplifier stage and the ends of the secondary winding of transformer 53 are connected to the grid and to the cathode of an electronic amplifier tube 54. A grid biasing battery 56 is connected between the cathode and the secondary of transformer 53 to bias the grid of the tube below the cut-off value so that plate current will not flow in the tube when signaling currents are not being received.

The plate of amplifier tube 54 is connected through the Winding of a slow-operating relay 51 to one pole of a plate battery 58, the other pole of which is connected to ground. An output circuit from the plate of tube 54 includes the condenser 59 and the primary windings of output transformers 6|, 62 and 63 in series. The free end of the primary winding of transformer 63 is connected to ground.

, The secondary winding of transformer 6| is connected across two filter circuits, one of which includes the inductance 64 and capacitance 66 and the other of which includes the inductance 61 and capacitance 68. Similarly, the secondary winding of transformer 62 is connected across filter circuits consisting of the inductance 69 and capacitance II, and of the inductance l2 and capacitance l3, and the secondary of transformer 63 is connected across two filter circuits including inductance 14 and capacitance 16, and inductance 11 and capacitance 18. The inductances and capacitances in the six filter circuits have such values that each filter circuit responds to and passes oscillatory current at the frequency generated by one of the vibratory reeds 31 and rejects the oscillatory currents generated by the other five reeds. Thus the oscillatory currents at the six different frequencies which may appear in the output circuit of amplifier tube 54 are separated by the six filters. One side of the filter which comprises the inductance 64 and capacitance 66 is connected to one of the cathodes of a cold cathode electron discharge tube 8| and the other side of the filter is connected through resistor 82 to ground. Similarly, one side of each of the other filter circuits is connected to one cathode of a discharge tube, the tubes being designated by the reference numerals 83, 84, 86, 81 and 88. The other side of each of the remaining five filters is connected through the resistor 82 to ground and the second cathode in each of the six discharge tubes 8|, 83, 84, 88, 81 and 88 is connected to ground.

The output electrode or anode oftube 8| is connected to one end of the winding of a relay 9| and the other end of the relay is connected through conductor 92 to the front contact of slow-operating relay 5'! previously identified as being included in the plate current circuit of amplifier tube '54. Similarly, the output electrodes of the discharge tubes 83, 84 and BBQ-to 88 are connected to one terminal-of the respec-,- tiverelays 93,- 94, 96, 91 and and the other t rminal of; each of those relays -is connected.

/ means of which a positive biasing potential becomes connected to each of the discharge tube cathodes, that is, connected to and controlled by an associated filter. Thus a potential difference is impressed between the two cathodes in each tube which is equal to the potential difference across the resistor 82.

- The relays 9|, 93, 94, 96, 91 and 98'constitute selector relays for controlling the selection of a character to be printed or a function to be performed by the receiving printing recorder.

Referring again to Fig. 2 is is to be noted that each of the key levers I8; whether it is a character, function or spacing key lever, is connected by a link IN to the armature of a magnet I02. The magnet I02 has been shown as being of the solenoid type, with a coaxial armature movable endwise or axially through the magnet winding upon energization of the magnet. It will be understood that these magnets could be of other.

types, but the solenoid magnet is a convenient form to be used where space considerations are involved, as they might be in the case of closely grouped magnets for operating key levers, since it is not necessary to afford space for pivoted armatures. .Each of the key levers is provided with a connection, indicated in Fig. 2 symbolically by the fragments of rods or links I03, for

operating the particular .element or mechanism function mechanism, such as shift, unshift, carriage return, line feed and any other function which the printing recorder may include.

. It may be noted at this point that typewriting machines controlled by keyboards are well known which have key lever controlled power actuated means for performing those functions which are not ordinarily adaptable to direct operation by key levers, outstanding examples of 'which are the carriage return .and. line feed functions. Well-known types of printing telegraph recordersalso have power actuated means for performing these functions, although such means are not generally controlled directly by key levers but are controlled instead by signal combinations generated through the operation of the key lev-.

The signal responsive function controlling ers. elements of such printing telegraph recorders are usually of such simplicity that they could readily be controlled directly by key levers and, accordingly, itis presumed to be unnecessary to specifically illustrate or describe hereinpower actuated means for performing the more complex of the functionsbut that function controlling and operating means of the form known in tical rows of seven magneta'giving a total of forty-nine magnets which the arrangementof six selectingrelaysresponsivc to six oscillatory;

current frequencies is readily adapted to control; As shown in Fig. 2 the magnets I02 would in all probability not be arranged as shown in Fig. 1' but the arrangement in Fig. 1 affords a convenient means of illustrating the selecting principle involved.

Selecting relays M, 9-3 and 94 are providedwith one, two and four contact tongues respectively which are operable between back and front contacts with the exception that the ex-- treme left-hand contact tongue of relay 94' has" no back contact. The single contact-tongue of relay 9| is connected to ground and by the operation of the three relays in permutational combinations ground may be applied through fan circuits controlled by the contact tongues to any one of the seven conductors I03 extending from the seven contacts with which the contact tongues of relay 04" cooperate. Each of the conductors I03 is connected to one end of the winding' of every magnet in one of the vertical rows of magnets I02 and as there are seven vertical" rows; each conductor I03 servesto' prepare energizing circuits for seven magnetsin any vertical row of the forty-ninemagnets I02.

Relays 96, ST and 08 are provided with one. two and four contact tongues respectively, and each of the contact tongues is operable between back and front contacts with the" exception of the extreme left-hand contact tongue of relay 98 which has only a front: contact. The single contact tongue of" relay 96 is connected to grounded battery I04 and the contact tongues? of the relays 86, 91 and 98 control fan circuits identical with those controlled by the relays BI, 03 and 94 to apply battery to the seven conductors I05 connected to the seven contacts of. relay 98. Each of the conductors I is connected to the opposite ends, from those to which the conductors I03 are connected, of the windings of the seven magnets in one of' the horizontal rows of magnets. I02. Since there are seven horizontal rows: of the magnets, each of the conductors I06 serves one ofthe rows In the operation or the receiving. system shown in Fig; 1, code combinations of two or more oscillatory currents at different frequencies are. received from station t over communication.

channel II through key I3 positioned in the.

receiving condition, which is the condition shown in Fig. l and the received frequencies are;

impressed upon the primary winding of transformer 53. are induced in the secondary or transformer 53 and are impressed between the grid and cathode of the amplifier tube 54. Unidirectional current pulsations corresponding to the oscillatory cur"- rents appear in the plate circuit of amplifier tube 54'' and corresponding pulsating potentials are impressed upon the output circuit which includes the condenser 69 and the'primary'win'dings of transformers BI, 62 and 63 in series.

The pulsations induce corresponding currents Corresponding oscillatory currents The potentials may be i-nsufiici'ent to cause breakdown: of the: tube, or theymay cause breakdown between the two cathodes; but untiIsl'ow-operati ng relay 51 operates and applies positive battery to'the outputanode's of the-tubes, current' for'opcrating the selector relays cannot flow; The path for energizing the selector relays; whencompleted by relay 51, is from grounded battery 58' through the contacts of relay 51, conductor 92, selecting relays, anodes of" the discharge tubes; ionizable discharge path in the tubes and grounded cathodes of the tubes to ground.

Slow-operating rela-y 51 which is included in the plate current circuit of amplifier tube 54'-responds to the fiow of current in that circuit re sulting from the reception of signals and attracts its contact tongue into engagement with the single front contact, thus connecting battery 53' over'battery conductor 92" and through the selecting relays 9|, 93, 94, 96, 9-'I and 98 to the anodes ofthe discharge tubes. Thus th output circuits for the discharge tubes are completed. At" the same time; a biasing potential is applied to the control cathode of each tube, this poten tial'. being insufficient to break down the tubes except those influenced and assisted by the oscillatorypotentials, and in the latter tubes cur-- rent for energizing the selector relays fiows from battery and will continueto flow even after theoscillatory-potentialshave been removed from the control cathodes. The received signal includes a frequency tocause the energization of at least one of the relays- 9I', 93 and 94 and a frequency to cause the energization of at least oneof the relays'lfi, 9 1 and 98. As a result of the soles-- tiv'e operation of'the relays 91, 93 and 94- groundw is connected through one of the seven conductors I03 to the windings of'the magnets I02 inone of the seven vertical rows. Through the seiec' ti-Ve operation of' the relays 95 0!- and- .lIf-battery I04 is connected through one of the-conductors I06 to the seven magnets I02 in one of the horizontal rows. Accordingly, that one of the magnets I02 whichis connected to the selectively grounded conductor I03 and to the selectively battery connected conductor Illtwil-l have its en ergizing circuit completed and will be energized to effect the operation of its associated key'lever I 8 (Fig. 2') and the operation of the type bar or'function controlling'element to which the key lever is connected, Only oneo'f the magnets [02 will be energized because no two of the magnets are connected tothe same ones of the conductors:

I'03 and I06.

The purpose in making relay 51 slow to operateis to withhold anode battery from the discharge tubes momentarily so that all required tubes shall be receiving the oscillatory c0ntrolling potentials before the tubes are permitted; to fire, whereupon they fire simultaneously. This prevents momentary'impulses, or signals, in which some of the oscillatory'currents may sufier slight delays in reaching and influencing the control electrodes of their respective discharge tubes, from firing one or more tubes less than the full code; which might cause an incorrect one of the mag-- nets I02 to operate. Since the control cathodes have no control over the tubes after they have fired, and the tubes can be rendered inactive only by substantially reducing or removing the anode potential, selecting conditions initiated by extremely short impulses may be prolonged, for a s'uflicient interval to assure operation ofa mag;

net- I02} by, making relay'5 1 alsoslow to release,

involving six signaling conditions representing two groups'of three selecting signals wherein at least one signal from each group is employed for effecting a selection. employed as a selective condition," since the normal deenergized condition of'the selecting relays 9|, 93, 94, 96, 91 and 98 corresponds to the blank signal, and this accounts forthe fact that the extreme left-hand contact tongue of each of the relays 94 and 98 has no back contact, and no magnet corresponding'to the magnets I 02 is to be energized in the idle condition of the receiving printer. s

The forty-nine selections that are afforded by the forty-nine magnets I02 fully accommodate the operation of a typewriting machine. Standard commercially available typewriters usually have forty-twoprinting type bars and forty-two key levers for controlling the type bars. The spacing function and the shift, unshift, carriage return, and line feed functions require five additional codes and bring the total to forty-seven.

This leavestwo codes which may be assigned to other special functions such as back space and tabulating functions. If a smaller number-of selective possibilities is required, such as for the control of recording printers corresponding to certain commercially available telegraph'printers, which are sometimes controlled by keyboards having three banks of keys, which do not print lower case letters, and which record figures and I certain punctuation characters as shift selections.

the number of magnets I02 may bereduced and certain of the conductors I03 and I06'and their associated paths through the fan circuits controlled by the selecting relays may be omitted.

With the selecting system above described, several key levers I8 of the transmitter will operate two of the code bars 28, the majority will operate three or four code bars, a feww'ill operate five code bars, and one may operate six. The touch of the keyboard probably will vary according to the number of code bars';operated. The codes involving the operationof greater numbers of code bars will preferably be assigned to the key levers pertaining to the characters or functions having the lower frequencies of use, so that the average keyboard eifort may be kept at a minimum.

. A modified ,form of keyboard transmitter for generating code combinations of oscillatory signaling current is shown in Fig. 5. Key levers III are pivoted on common pivot rod H2, are provided with key tops H3 and are connected by links II4 to operating magnets IIB, this portion of the structure being identical with that shown in Fig. 2. Key levers III are made of electrically conductive metal and are Supported in electrically conductive relation to the 'pivot rod II2, which is grounded.

Below the key lever III and extending transversely thereto from one side of the keyboard to the other a plurality of conductive wires II1 equal in number to the number of oscillatory currents involved in the code is supported'by non-conductive blocks H8. Tension springs H8 are interposed between one end of each of the wires H1 and one of the blocks II3 for maintaining the wires II 1 yieldably taut.

The signaling current generator, designated generally by the reference numeral I2I, includes The blank signal is not an elongated permanent magnet I22, vibratory reeds I23 supported by clamping blocks I24 within magnet I22, and a pick-up or 'current generating winding I26 for which the vibratory reeds I23 serve as driving armatures. The signaling current generator I2I may be substantially identical with the signaling. current generator 38 shown in Figs. 2, 3 and 4, as fara's the elements thus far identified in'the generator I2I are concerned; 1

Adjacent to the free ends of the vibratory reed I23 the permanent magnet I22. supports a plurality of laminatedelectromagnet cores. I21 each of which is provided: with an energizing winding-I28. One terminal of each of the windings I28 is connectedto grounded battery and the other terminal is connected to one ofthe conductive Wires II1. Each of the magnet cores I21 has-an end presentedadjacent 'tothe-flat surface near the free end of its associated vibrat'oryreed I23 as a pole face and the reeds-I23 serve as armatures for the, electromagnets I21.

The key levers I I I are provided with'variously disposed depending lugs 129 which, upon the operation of a key lever, engage and slightly dee press and thereby firmly contact corresponding ones of the taut wires' Ill -thus. completing energizing circuits. for-corresponding ones of the electromagnets I21 from ground through the key lever III and its lugs I29, wires II1, springs H9, and windings of the corresponding ones of electromagnets I21 to grounded battery. Thus certain of the electromagnets I21 are energized according to lthe code to be transmitted and they attract and hold the corresponding vibrae The attracted. reeds I23 are.

tory reeds I23. held by the electromagn ets I 21 until the operated key lever. III is released and the; energizlowed to vibrate for the generation of. the signaling currentswhile the key levers are held depressed, as in the embodiment of the invention shown in Figs. 2, 3 and 4, are merely flexedand held upon the depression of a key lever and are released to permit free vibration-upon the release of the key lever.

Although the vibratory reed; type of signaling current generator has been shownherein as adapted tobe controlled by a keyboardinechanism, it will be understood that the signal'generator may, readily be controlled from at'tape sensing mechanism or other type ofstored-signal sensing device. For example, the vibratory reeds, 31 of the signal generator 38 shown in Figs. 2, 3 and 4 may be plucked by'the'sens ing levers of a tape sensing mechanismas the sensing fingers of'the' levers enter code perforations in a perforated tape; In the case' of the signal generator I 2|, the transmitting contacts of the well-known perforated tape con trolled transmitter may be connected directly-t0 the electromagnets I21 "of the signal generator I2I and underthese circumstances the vibratory" reeds I23 will be attracted'when-the tape sensing pins enter the perforations in the tape drawn preparatory to advancement of the tape to bring the next set of code perforations into position to be sent.

Although certain specific embodiments of the invention have been illustrated in the drawings and described in the foregoing specification, it will be understood that the invention is not limited to such specific embodiments, but is capable of modification and rearrangement without departing from the spirit of the invention and within the scope of the appended claims.

What is claimed is:

1. In a telegraph system, a signaling channel, a plurality of normally deactivated means for generating different frequencies, means for selectively activating combinations of at least two of said frequency generating means simultaneously to generate a telegraph signal code combination, means for impressing the frequencies generated thereby on said channel, means connected to said channel for receiving and amplifyingsaid frequencies, means for separating said amplified frequencies, relay means individually responsive to said separated frequencies, a plurality of printing elements, and means selectively operable by combinations of said relay means for operating said printing elements individually.

2. In a telegraph system, a signaling channel, a plurality of normally deactivated means for generating di'iierent frequencies, means for selectively activating combinations of at least'two of said frequency generating means simultaneous'ly to generate a telegraph signal code combination, meansresponslve to said frequency gen-- erating means for generating oscillatory currents corresponding to said frequencies and for impressing said oscillatory currents on said channel, means connected to said channel for receiving and amplifying said currents, means for separating said amplified currents according to frequencies, electronic relay means responsive to said separated oscillatory currents, electromagnetlc relay means controlled by said electronic relay means, a plurality of printing elements, and

means operable by combinations of said electromagnetic relay means for operating said printing elements individually.

3. In a telegraph system, a signaling channel, a plurality of normally deactivated means for generating diflerent frequencies, means for selectively activating the two or more frequency generating means involved in any selecting code simultaneously, means responsive to said frequency generating means for generating oscillatory currents corresponding to said frequencies and for impressing said currents on said channel, means connected to said channel for receiving and amplifying said currents, means for separating said amplified currents according to frequencies, first relay means responsive to said separated currents, second relay means controlled by said first relay means, a plurality of printing elements, and electromagnets operable by two or more of said second relay means in combination for operating saidprinting elements individually.

4. In a telegraph system, a signaling channel. a plurality of vibratory elements having different natural frequencies of vibration, means for selectively setting at least two of said vibratory elements in vibration simultaneously for generating at least two different frequencies, means controlled by said vibratory elements for generating oscillatory currents corresponding in frequency to the frequency of vibration of said elements and for impressing said currents on said channel,

means connected to said channel for receiving and amplifying said currents, means for separating said amplified oscillatory currents according to their frequencies, relay means responsive to said separated oscillatory currents, a plurality of printing elements, and electromagnets individual to, said printing elements and operable by combinations ofsaid relay means for operating said printing elements.

5. In a telegraph system, a signaling channel, normally inactive means for generating a yplurality of frequencies in the audible range, means for selectively activating simultaneously only the twoor more of said frequency generatin means involved in any selecting code, means for generating oscillatory currents corresponding to the audible frequencies generated by the operated ones cfsaid frequency generating meansand for impressing said currents on said channeLan electronic amplifier connected to said channel for receiving and amplifying said oscillatory currents, a plurality of oscillatory current filters having characteristics to pass said amplified oscillatory currents individually rand-connected to the output of said electronic amplifier, firstrelay means responsive individually to the current passed by said filters, a second relay means controlled by each of said first relay means and operable by current therefrom, a plurality'of printing elements, and an electromagnet individually associ ated with said printing elements and operable by two or more of said second relay means in combination foroperating said printing elements- 6. In a printing telegraph system, a plurality of manually operable key levers, .a plurality of code bars, means associated with said. key levers for operating said code bars combinations, a plurality of vibratory elements equal in number to the number of code bars, means carried by eachcode bar forsetting in vibrationone of said vibratory elements, means associated with said vibratory elements for generating oscillatory signaling currents :at frequencies corresponding to the frequency of vibration of said vibratory element, means for selectively dividing said signaling currents, and a printing mechanism selectively controlled by said divided currents.

'7. In a printing telegraph system, a plurality of 'manually operable key levers, a plurality of code barsless in number than the number of key levers, means associated with said .key levers for operating said code bars in combinations, a plurality of vibratory elements equal in number to the number of code .bars and havingdifierent natural frequencies of vibration in the audible range, means associated with each code bar for setting one of said vibratory elements in vibration, means common to all of said vibratory elements for generating signaling currents at frequencies corresponding to the frequencies of vibration of said vibratory elements, means for selectively dividing said signaling currents, and a printing mechanism selectively controlled by said divided currents.

8. In a printing telegraplrsystem, a plurality of code elements operable in various combinations, a plurality of vibratory elements equal in number to the number of code elements and having diiferent natural frequencies of vibration in the audible range, means associated with said code elements for setting said vibratory elements in vibration, means for generating oscillatory signaling currents at frequencies correspondnig to the frequencies of vibration of said vibratory elements, means for selectively dividing said signaling currents, and a printing mechanism selectively controlled by said divided currents.

9. In a printing telegraph system, a plurality of code elements operable in combinations, a plurality of vibratory elements equal'in number to the number of code elements and having different natural frequencies of vibration, means controlled by said code elements for setting corresponding ones of the vibratory elements in vibration, means controlled by said vibratory elements for generating oscillatory signaling currents at frequencies corresponding to the natural frequencies of vibration of said vibratory element, means for selectively dividing said signaling currents, and a printing mechanism selectively controlled by said divided currents.

10. In a printing telegraph system, a plurality of code elements operable in combinations, means for generating a magnetic field, a plurality of armatures mounted to vibrate in said magnetic field, said armatures having different natural frequencies of vibration, means controlled by said code elements for setting individual ones of said vibratory elements in vibration, an electrically conductive winding associated with said armatures for generating oscillatory signaling currents at frequencies corresponding to the natural frequencies of vibration of said armatures in response to vibration thereof, means for selectively dividing said signaling currents, and a printing mechanism selectively controlled by said divided currents.

11. In a telegraph transmitter, a plurality of manually operable key levers, a plurality of yieldably supported conductive strands extending transversely of said key levers, a corresponding plurality of electromagnets connected individually to said conductive strands, a source of electrical potential having one side connected to said electromagnets and the other side connected to said key levers, means associated with said key levers for selectively engaging said conductive strands to complete the circuits of said electromagnets in various combinations, a vibratory armature for each of said electromagnets having a natural frequency of vibration different from the frequency of vibration of each other armature, and means responsive to vibrations of said armatures for generating oscillatory signaling currents at frequencies corresponding to the frequency of vibration of said armatures.

12. In a telegraph transmitter, a plurality of manually operable key levers, a plurality of yieldably mounted conductive strands, less in number than the number of key levers, extending transversely of said key members, a plurality of electromagnets corresponding to the number of said conductive strands and individually connected to said strands, a source of potential having one side connected to said electromagnets and the other side connected to said key levers, means conductively associated with said key levers for conductively engaging said strands in various combinations to complete the energizing circuits of said electromagnets, a vibratory armature for each of said electromagnets movable into engagement therewith upon the energization of the electromagnet and releasable upon the deenergization of the electromagnet for free vibration, each armature having a natural frequency of vibration different from those of the other armatures, and pick-up coil means associated with said armatures for generating oscillatory signaling currents at frequencies corresponding to the frequency of vibration of said armatures.

13. In a printing telegraph apparatus including a plurality of printing elements, a plurality of manually operable key members connected to said printing elements, a plurality of code elements controllable selectively in combinations by said key'levers, a plurality of vibratory elements corresponding in number to the number of said code elements and having different natural frequencies of vibration, means controlled by said code elements for setting said vibratory elements in vibration, a communication channel, means associated with and controlled by said vibratory elements for generating oscillatory currents at frequencies corresponding to the frequencies of vibration of said vibratory elements and for impressing said currents on said channel, means for receiving oscillatory currents from said channel, means for separating said received oscillatory currents, relay means individually controlled by said separated currents, and a plurality of elec-- tromagnets individually connected to said key levers and operable under the control of combinations of said relay means to operate said key levers and thereby to operate the printing elements associated with said key levers.

14. In a printing telegraph apparatus including a plurality of printing elements, a plurality of manually operable key members connected to said printing elements, a plurality of code elements controllable selectively in combinations by said key levers, a plurality of vibratory elements corresponding in number to the number of said code elements and having different natural frequencies of vibration, means controlled by said code elements for setting said vibratory elements in vibration, a communication channel, means associated with and controlled by said vibratory elements for generating oscillatory currents at frequencies corresponding to the frequencies of vibration of said vibratory elements and for impressing said currents on said channel, means for receiving oscillatory currents from said channel, means for separating said received oscillatory currents, relay means individually controlled by said separated currents, a plurality of electromagnets individually connected to said key levers and operable upon the control of combinations of said relays to operate said key levers and thereby to operate the printing elements associated with said key levers, and means for alternatively and selectively connecting said oscillatory current generating means or said oscillatory current receiving means to said channel.

15. A printing system comprising a reed frequency transmitter adapted to produce combinations of alternating current frequencies in accordance with the character to be printed, means for amplifying said frequencies, means for selectively dividing said frequencies, and a printing mechanism selectively controlled by said divided frequencies.

16. In a telegraph transmitter, a plurality of manually operable key levers, a'plurality of electromagnets less in number than the number of key levers and controllable in combination thereby, a vibratory armature for each of said electromagnets having a natural frequency of vibration different from the frequency of vibration ofeach other armature, and means responsive to vibrations of said armatures for generating oscillatory signaling currents at frequencies corresponding to the frequency of vibration of said armatures.

17. In a telegraph transmitter, a plurality of manually operable key levers, a plurality of elec- 18. A printing system comprising a vibratory reed transmitter adapted to produce com-binations of mechanical vibrations in accordance with the character to be printed, means for generating oscillatory currents corresponding to said vibrations, means for selectively dividing said currents, and a printing mechanism selectively controlled by said divided currents.

PAUL B. MURPHY. 

